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Stayin' alive, without antigen [復制鏈接]

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樓主
發表于 2009-3-5 23:35 |只看該作者 |倒序瀏覽 |打印
Martin/Macmillan# ?" }. D+ W# i# T1 l  D

% L$ H1 C& L4 z. Q/ K* G$ f+ u( AWhen a T cell meets a dendritic cell that carries an antigen, the meeting activates the T cell to battle pathogens. Less certain is what happens when the dendritic cell doesn't have antigen. Now, two reports bolster the controversial hypothesis that this kind of antigen-free cell-to-cell contact is necessary for the survival of T cells.: r" S/ R/ x2 E& ?$ Z

  d8 U! @! o- h: R. S3 lRoland Martin and colleagues of the National Institute of Neurological Disorders and Stroke in Bethesda, MD, found that contact with an antigen-free dendritic cell provokes dramatic changes in human memory T cells〞though not as profound as activation by an antigen. Gene expression shifts, boosting production of cytokines such as interferon gamma, and some T cells begin to divide slowly. Most importantly, the meeting lengthens the life of memory cells, more than doubling the percentage that survive five days in culture.  x0 U3 r, E- R' I% f- D
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Working with naive mouse T cells, a team led by Alain Trautmann of the InstitutCochin de Génétique Moleculaire in Paris, France, saw similar results: greater survival and low-level proliferation in the T cells. "In the normal life of a lymphocyte, it will interact repeatedly with dendritic cells," Trautmann says. "These repeated meetings are essential for survival." To their surprise, the authors also detected a structure known as an immunological synapse at the junction between the cells. The synapse normally forms when a dendritic cell stimulates a T cell, but its formation was thought to require antigen.
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Both groups agree that cellular contact may boost the immune system's readiness in two ways. By stimulating survival and slow reproduction, the interaction may help maintain stocks of T cells. And the low level of stimulation provided by dendritic cells seems to prime lymphocytes for action. However, Martin believes that the work also exposes a possible downside. He thinks that the surge in cytokine production may increase the risk of autoimmune diseases like multiple sclerosis in susceptible individuals. "The interaction may set up a certain environment that is conducive to the pro-inflammatory reactions that you see in autoimmune diseases," he says.) |# s- V. f, \: q1 X

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' r1 B1 i7 i6 r& kKondo, T., et al. 2001. Nat. Immunol. 2:932–938.& V# D4 Z; K" B/ w% g
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Revy, P., et al. 2001. Nat. Immunol. 2:925–931.
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3 l# ~- Y/ ?  e; IMitch(Even antigen-less dendritic cells can si)

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發表于 2015-5-25 16:01 |只看該作者
水至清則無魚,人至賤則無敵!  

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藤椅
發表于 2015-6-9 19:09 |只看該作者
謝謝分享  

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板凳
發表于 2015-6-12 17:01 |只看該作者
干細胞之家微信公眾號
不早了 各位晚安~~~~  

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報紙
發表于 2015-6-18 06:43 |只看該作者
給我一個女人,我可以創造一個民族;給我一瓶酒,我可以帶領他們征服全世界 。。。。。。。。。  

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地板
發表于 2015-6-29 12:01 |只看該作者
@,@..是什么意思呀?  

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發表于 2015-7-23 22:31 |只看該作者
看或者不看,貼子就在這里,不急不忙  

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發表于 2015-8-2 18:52 |只看該作者
在線等在線等  

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發表于 2015-8-9 19:24 |只看該作者
寫得好啊  

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發表于 2015-9-4 17:46 |只看該作者
頂.支持,路過.....  
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